Laterally spaced electrode mounts for electron guns



March 8, 1966 V J. H. JOHNSON v 3,239,793

LATERALLY SPACED ELECTRODE MOUNTS FOR ELECTRON GUNS Filed Jan. 5, 1965 INVENTOR hy zz/zfl da ATTORNEYIj United States Patent LATERALLY SPACED ELECTRODE MOUNTS FOR ELECTRON GUNS Jay H. Johnson, Gwenshoro, Ky., assignor to Kentucky Electronics Inc, Owenshoro, Ky., a corporation of Kentucky Filed Jan. 5, 1965, Ser. No. 423,430 3 Claims. (Cl. 313-32) This invention relates to cathode ray tubes and more particularly to the construction of electron gun assemblies.

Because of attempts to miniaturize television sets and even in large sets the attempt to reduce the length of the picture tube, it is desirable to produce a smaller electron gun. However, this is attended by dimensional problems since closer spacings of electrodes requires better tolerances in dimensional mounting of the electrodes; and former assembly techniques tend to provide a large number of rejects.

It is therefore an object of this invention to provide improved electron guns which can be made within very close tolerances.

Another object of this invention is to provide electron gun assemblies which may be made smaller and shorter than with conventional techniques.

Thus in accordance with this invention, the various electron gun parts are mounted between and afiixed to two longitudinal glass rods. Formerly such parts were held by a single strap; or when more firmness was required, dual straps were mounted with vertical spacing along the rods. This sort of mounting technique permitted slight misalignment of the parts relative to the axis of the beam as caused by relative bending and displacement of parts under the stress of thermal expansion or vibration. Such variations are not tolerable when smaller guns are formed and closer tolerances are required. Even in the alignment process of these electron gun parts when the parts were bent into alignment by malforming the straps, a certain degree of elasticity in the straps occurred which could cause the parts to change position after alignment in the most critical dimension of twist about the axis of the electron beam, and thus limited the attainment of desired close tolerances. Even when using former dual straps mounted along the axis of the beam in small guns, the spacing between parts hecame so small that the span decreased; and little of the desired axial firmness was imparted.

These deficiencies are corrected in this invention by using dual mounting straps each having two prongs spaced with an arcuate spacing span on the electrode laterally positioned in a plane perpendicular to the electron beam with both prongs embedded in a single widened rod. Thus, no matter how closely the relative parts are spaced together, an optimum span can be attained for mounting each electrode. Furthermore the relative positional dimensions of such mounted parts are not subject to change in the presence of heat or vibration. This novel technique therefore permits precise dimensioning between the parts of an electron gun within much closer tolerances than heretofore provided by conventional mounting techniques, and prevents critical dimensional changes of parts relative to the axis of the electron beam.

The mounting technique aflforded by this invention is illustrated in detail in the accompanying drawing, wherein:

FIGURE 1 is a side view, partly in section, of an electron gun assembly; and

FIGURE 2 is a top view, in section, taken along lines II-II of FIGURE 1.

The relationship of cathode 3, mounted in ceramic 3,239,708 Patented Mar. 8, 1966 'ice disc 4 and held within grid cup 5 with other electrodes 6, etc, mounted axially along the path 7 of the electron beam is shown in FIGURE 1. The cathode 3 is conventionally mounted within grid cup 5, but this grid cup and all other beam forming electrodes 6, etc., are mounted onto glass rods 8 and 9 by straps 10 shaped as shown in FIGURE 2. The straps 10, 10' etc. are so constructed on all the beam forming electrodes in accordance with the concepts of this invention.

It will be noted that the glass rods 8 and 9 are constructed thinner and wider than conventional rods to receive the spaced prongs or arms 11 and 12 of the strap 10 extending from the outer surface of electrode 14 in a span spaced transversely in a plane perpendicular to the beam axis as shown in FIGURE 2. The strap is welded to electrode 14 at its inner extremity over a curvature following the contour of the electrode, and has its prongs 11 and 12 embedded in glass rod 9.

From the view of FIGURE 2 the mounting firmness may be noted since it is diificult to visualize any possibility of twist of the electrode 14 with respect to the axis 7 of the electron beam.

As seen in FIGURE 1 from positioning of straps 10' and 10", even when the second grid 6 becomes very narrow, there is little problem of mounting closely with grid cup 5. Thus, this mounting technique permits use of smaller parts and closer spacing while giving more rigidity, and for the first time, produces a satisfactory mount for decreasing the number of rejects due to poor dimensional tolerances even when using a shorter gun.

The salient features of this invention reside in a strap mounted on a beam forming electrode such as a grid or focus anode and having two laterally positioned prongs for insertion into a single glass rod located parallel to the beam.

Having therefore provided novel features advancing the state of the art, they are defined with particularity in the following claims.

What is claimed is:

1. In an electron gun assembly with a series of apertured beam forming electrodes mounted to define at least one electron path disposed between at least two insulating mounting rods, the improvement comprising, widened rods, and mounts afiixed to said apertured electrodes at a plurality of positions each with two spaced arms extending from two positions on the surface of the electrodes in a plane substantially perpendicular to the electron beam path with said two arms embedded in each of the widened rods at two spaced positions transversely of said electron path in said plane in each rod.

2. An assembly as defined by claim 1 wherein the mounts are U-shaped strap members spaced on opposite sides of said electrodes to extend into the rods.

3. An assembly as defined in claim 2 wherein the electrodes are cup shaped and the strap members comprise an innermost portion having a surface with curvature following the cup shaped curvature of the electrodes affixed thereto at this surface.

References fiited by the Applicant UNITED STATES PATENTS 2,808,527 10/1957 McKenzie. 2,897,391 7/ 1959 Erskine. 2,909,689 10/1959 Case. 3,018,400 1/ 1962 Navatta et a1. 3,085,172 4/ 1963 Smith. 3,134,923 5/ 1964 Brown.

GEORGE N. WESTBY, Primary Examiner. V. LAFRANCHI, Assistant Examiner. 

1. IN AN ELECTRON GUN ASSEMBLY WITH A SERIES OF APERTURED BEAM FORMING ELECTRODES MOUNTED TO DEFINE AT LEAST ONE ELECTRON PATH DISPOSED BETWEEN AT LEAST TWO INSULATING MOUNTING RODS, THE IMPROVEMENT COMPRISING, WIDENED RODS, AND MOUNTS AFFIXED TO SAID APERTURED ELECTRODES AT A PLURALITY OF POSITIONS EACH WITH TWO SPACED ARMS EXTENDING FROM TWO POSITIONS ON THE SURFACE OF THE ELECTRODES IN A PLANE SUBSTANTIALLY PERPENDICULAR TO THE ELECTRON BEAM PATH WITH SAID TWO ARMS EMBEDDED IN EACH OF THE WIDENED RODS AT TWO SPACED POSITIONS TRANSVERSELY OF SAID ELECTRON PATH IN SAID PLANE IN EACH ROD. 